1. Field
Example embodiments relate to a semiconductor light-emitting device including an active layer. Other example embodiments relate to a nitride semiconductor light-emitting device including an active layer that has a multi-quantum well structure including a quantum well layer and a barrier layer.
2. Description of the Related Art
A device including a nitride semiconductor has a high melting point and is comparatively durable against heat. As such, the device is less dependent on temperature and may been used in light-emitting devices (e.g., light-emitting diodes (blue/green light-emitting diode) and laser diodes) and high-speed switching, high-power electronic devices.
In general, compound semiconductor light-emitting devices include an active layer that converts a current to light. The active layer of a nitride semiconductor light-emitting device emitting blue light is generally formed of indium gallium nitride (InGaN). The band gap energy of the active layer is controlled by varying the composition of indium. As such, the light-emitting wavelength region can also be controlled.
An active layer of a compound semiconductor light emitting device includes a quantum well layer and a barrier layer. The active layer has a single quantum well structure or a multi-quantum well structure.
The multi-quantum well structure includes a plurality of mini bands and can efficiently emit light at a lower current. The multi-quantum well structure has higher light-emitting power characteristics than the single quantum well structure.
An InGaN-based active layer includes a quantum well layer and a barrier layer that may have a stacked structure of InGaN/GaN and a stacked structure of InGaN/InGaN, respectively. The quantum well layer and the barrier layer may have a stacked structure of InGaN/AlGaN and a stacked structure of InGaN/InAlGaN, respectively. As the composition of indium in the InGaN-based active layer increases, the light emitting power is lower. As such, a new epitaxial technology for increasing the internal quantum efficiency of the active layer may be desirable.